A magnet (permanent magnet) is used as a component for producing a drive force for causing a diaphragm (vibrating plate) to vibrate in a dynamic headphone driver (also called a driver unit) or a loudspeaker. As this kind of permanent magnet, those manufactured by sintering a magnetic body are generally used.
On the other hand, development is underway of so-called bonded magnets that are obtained by molding rare-earth magnetic power such as neodymium (Nd) or ferrite particles using a thermoplastic resin such as a polyamide resin as a binder (for example, refer to Patent Literature 1 below).